1. Field of the Invention
This invention pertains to polyamide compositions and films made therefrom, having a high degree of transparency while maintaining their physical properties. More particularly, the invention pertains to polyamide compositions having high transparency while maintaining a high degree of crystallinity, good mechanical strength, high heat distortion temperature, and high flexibility.
2. Description of the Prior Art
It is known in the art to use polyamides or nylons for their unique properties, such as mechanical strength and thermoformability. In order to enhance the performance of most nylons, it is desirable to have a high degree of crystallinity. However, a high degree of crystallinity reduces the transparency of the nylon. Suppressing the degree of crystallinity in nylon is known to keep films made from nylon transparent. This has been accomplished by blending a polyamide with an amorphous, aromatic nylon. However, the resultant film has reduced physical strength due to the lower degree of crystallinity.
U.S. Pat. No. 4,404,317 teaches the blending of amorphous polyamide copolymers with semicrystalline polyamides to produce molding resins having enhanced properties. The various enhanced properties are dependent on the relative amounts of amorphous and crystallizable polyamides. U.S. Pat. No. 5,480,945 teaches single and multilayer nylon films utilizing blends comprising an amorphous nylon and a nylon copolyamide and having improved processability, shrinkage and optical properties. U.S. Pat. No. 4,556,696 teaches a process to form a polyamide film utilizing a blend of polyamides such as polyamides with terminal functionality including carboxylic acid group termination and amino group termination. U.S. Pat. No. 5,886,087 teaches transparent, colorless and amorphous polyamides, and their blends. These references teach the blending of polyamides for the purpose of changing properties of a nylon composition, but they do not teach the characteristics of the present invention which include good transparency and maintained high crystallinity. The present invention solves the problems in the prior art by providing a polyamide composition with improved crystallization rate while maintaining a high level of crystallinity and a high degree of transparency.